An image forming apparatus refers to an apparatus that prints print data generated by a printing control terminal device such as a computer on a recording paper. Examples of such an image forming apparatus include a copier, a printer, a facsimile, or a multifunction peripheral (MFP) that combines functions of the copier, the printer, and the facsimile through a single device.
Generally, such an image forming apparatus performs a printing operation using a plurality of types of recording medium. Thus, the image forming apparatus has printing conditions such as a conveyance speed, a transfer condition and a fixing condition suitable for various kinds of printing paper and performs printing by changing the printing conditions according to types of printing paper.
In the image forming apparatus, it is necessary to determine or set the types of printing paper in advance to perform printing under appropriate printing conditions. To determine such printing paper, a technique for determining the types of printing paper using data output from an optical sensor has commonly been used.